Tiered storage unit



FIG. 1 is a perspective view of a tiered storage unit showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a perspective view with the middle and bottom storage doors opened for convenience of illustration. 

The ornamental design for a tiered storage unit, as shown and described. 